Wood chipper disc and knife mounting



United States Patent 11113,s42,302 I [72] Inventor Frank Louis Salzmann,Jr. 5 References Cited Lomb AYE. W. P40. 80X UNITED STATES PATENTS [2]] A I No ggg ggfi 35208 2,712,904 7/1955 Dnrkee 144/1 76X 22 riigd Sept 11, 1968 3,000,578 9/1961 Rlches et al. 241/92 Patented Nov. 24 1970 3,144,995 8/1964 Fontarne 241/298 Primary Examiner-Donald R. Schran Attorney-Lawrence L. Colbert [54] WOOD CI-IIPPER DISC AND KNIFE MOUNTING 6 Claims, 4 Drawing Figs.

[521 1.8. CI- 241/298; ABSTRACT; A chipper disc assembly wherein {he chipper 144/ l 76. 144/2 l 8; 241/92 knives are very securely held to withstand the constant pound- [51] Int. Cl 302C 7/12; ing of the log and readily replaceable wear plate segments are B27g 13/08 provided between adjacent knives on the disc, rendering [50] Field OfSQIICIl I44/I76, maintenance economical and reducing the need for knife ad- 162, 218, 219; 241/298, 296, 92 justment.

Patented Nov. 24, 1970 Sheet WOOD CHIPPER DISC AND KNIFE MOUNTING Disc type wood chippers for reducing logs and the like to usable chips for the paper pulp industry are quite well known. Examples of such machines are shown in prior US. Pat. Nos. 1,906,486; 2,712,904; 3,144,995 and 3,297,067.

While generally successful, such machines have suffered from certain deficiencies notably 'in connection with the mounting of the chipping knives on the heavy rotary steel or cast iron disc which constitutes the heart of the chipping machine.

It has proven very difficult to clamp the'chipper knives securely to withstand the heavy pounding inherent in the chipping operation and to minimize the need for frequent knife tightening and adjustmentfAttempts to improve this situation have resulted in structures whichare unduly complicated and require complex machining and increased numbers or parts which cannot be justified economically.

The present invention aims to overcome these prior art defects through theprovision of a greatly improved chipping knife mounting and carrier disc which is extremely sturdy and durable, relatively simplified in construction and having means to accommodate the excessive wear caused by the engagement of the log with the disc during rotation of the latter.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings wherein like numerals designate like parts, the numeral designates the machine base and lower housing section, the companion top cover 11 being shown separated from the base in FIG. 4 and carrying the wood chip discharge duct 12. The usual log infeed spout 13 is carried by one side of the base 10 and the cutting disc assembly 14 to which the present invention is specifically directed is mounted on a main rotary shaft supported'by the base 10. The above general organization is conventional as depicted in any of said prior patents and need not be dealt with in further detail herein.

The chipper knife disc assembly 14 includes a disc body 15 of steel or the like having plural circumferentially equidistantly spaced chip slots 16 formed therethrough. Adjacent one side of each slot 16, the disc body 15 is provided in one face with a relatively deep square cornered recess 17 for the accommodation of a knife holder 18, knife clamp 19, chipper knife 20 and counter knife 21. The elements 18 through 21 are securely seated in assembled relationship on the slightly slanting bottom face ofthe recess 17 and are maintained rigidly secured to the disc body 15 by means of Allen screws 22 or like fasteners.

It should be mentioned here that the number of slots 16 and chipper knife assemblies have been shown in the drawings as the preferred arrangement but this number is not critical and in some instances the number may be smaller or greater.

Referring particularly to FIGS. 2 and 3, each knife assembly has its holder 18 recessed to provide stepped parallel seating faces 23 and 24 for the aforementioned knives 20 and 21 whose opposed faces are also in contacting relation as shown in FIG. 2. The holder 18 further includes stepped shoulders 25 and 26 at right angles to the seating faces 23 and 24, against which adjusting screw stops 27 in the rear edges of the knives 20 and 21 abut. This allows the chipper and counter knives 20 and 21 to be adjusted for proper cutting engagement with the log and substantially locked 'after adjustment.

Theclamp 19 of generally triangular configuration has a diagonal face 28 contacting the chipper knife 20 over substantially the upper side of the latter for security. Another substantially right angular face 29 of the clamp contacts the shoulder 26 of the holder 18, and when the fasteners 22 are tightened up, a very secure gripping and wedging action is provided by the clamp 19 against the knives 20 and 21 and the underlying holder 18. Additionally the holder 18 is firmly anchored in its recess 17.

As best shown in FIG. 3, the rear edges of knives 20 and 21 are notched at 30 and 31 to provide clearance for the Allen screws 22 which extend through the assemblage of parts in FIG. 2 and into screw-threaded openings provided in the disc body 15.

As' shown in FIG. 2, the cutting leading edge 32 of chipper knife 20 projects about one-half the distance across the chip slot 16 and is angled to deliver the chips through this slot so that they may enter the housing and pass through the outlet 12.

An important feature of the invention resides in the provision of separate filler and wear plate segments 33 and 34 between each circumferentially spaced pair of knife assemblies and slots of the disc body. Each superposed pair of filter and 'wear plates is firmly anchored to the disc body 15 by recessed Allen screws 35 or by similar means whereby the outer faces of the wear plates 34 lie in a common plane slightly below the cutting edges 32 of the chipper knives. As shown, the plates 33 and 34 constitute equally-sized segments ofa circle and are shaped like pie slices. They effectively cover substantially the entire surface of the disc body on the side thereof which receives the log. The wear plate segments 34 are readily removable and replaceable as wear occurs and they render the maintenance of the disc assembly economical and convenient. Additionally, the thickness of the filler plates 33 may be changed if desired to regulate the knife setting. The arrangement of separate filler and wear plate segments renders the disc assembly versatile and economical and the only maintenance generally required is the replacement occa sionally of wear plates 34 and the sharpening or replacement of chipper knives. It is believed that the advantages and economies of the structure and the simplicity thereof will be recognized by those skilled in the art.

In view of the cited prior patents, it is believed that a description of the general mode of operation of the machine, which is conventional, is unnecessary herein.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Iclaim:

1. A chipper knife assembly for a wood chipping machine of the rotary disc type comprising a disc body having a chip slot formed therethrough on a radialline and having a recess formed therein at one side of the chip slot in the working face of the disc body, a holder seated within the recess and having a pair of diagonal stepped seating faces and a coacting pair of right angular stepped shoulder faces, a counter knife and a chipper knife resting upon the seating faces and being in opposed contacting relation, screw stop elements in the rear edges of said knives engaging said shoulder faces, a clamp element including a diagonal face contacting the outer side of the chipper knife over a major portion of the area of the latter and also contacting one of the shoulder faces, fastener means engaging through the clamp and holder and anchored to the disc body and securing the holder, clamp and said knives in rigid assembled relationship, the chipper knife extending diagonally beyond one wide wall of the slot to a point near the center of the slot with its cutting edge projecting outwardly ofthe working face of the disc body, a filler plate element on the working face of the disc body adjacent the sides of the holder and clamp remote from said slot, a wear plate element mounted on the tiller plate element and having an outer wear face substantially flush with an outer face of the clamp and said cutting edge, and means to secure the filler and wear plate elements to the disc body fixedly.

2. A chipper knife assembly as defined by claim 1 which includes a plurality of said chip slots, recesses and parts mounted therein disposed in circumferentially equidistantly space relation on the disc body, and said filler plate and wear plate elements arranged between adjacent pairs of slots and being equally sized and collectively covering substantially the working face of the disc body.

3, A chipper knife assembly as defined by claim 1 wherein said clamp has a wedge portion with one side of the wedge portion contacting the chipper knife and the other side contacting one of said shoulder faces of the holder.

4. A chipper knife assembly as defined by claim 1, wherein said counter knife-is narrower than the chipper knife and underlies the chipper knife and is beveled oppositely to the chipper knife and has a forward leading edge terminating inwardly of the cutting edge of the chipper knife and parallel thereto, the chipper knife cutting edge and counter knife beveled portion serving to guide wood chips into said chip slot of the disc body.

5. A chipper knife assembly as defined by claim 1. wherein said screw stop elements are set screws engaging within screwthreadcd openings in said rear edges and being independently adjustable.

6. A chipper knife assembly as defined by claim 1, wherein said fastener means comprises screws having their heads recessed in said clamp so that the exterior surface of the clamp is free ofobstructions. 

